Prop results on Yamaha F60 10 3/8" x 13P

[Dave S]

I was wondering if anyone had any suggestions on getting my new to me Arima 16' Sea Explorer dialed. Had it out today in Saanich Inlet. No real current, no wind, fairly glassy, average running weight.

Motor is a 2002 Yamaha F60, no trim tabs, motor height set right I think. (had it one notch deeper last outing and got little to no cavitation. moved up a notch and would only cavitate on hard turns. cavitation plate was just under water)

18 mph at 4200 rpm
19 mph at 4400 rpm
20 mph at 4600 rpm
24 mph at 5000 rpm
25 mph at 5400 rpm
27 mph at 5600 rpm
27.5 mph at 5800 rpm

Gets up on plane in about 8 seconds with 2 passengers. Old boat would get up easier but this boat weighs more and it's the same motor and prop.

So I emailed a guy in Seattle area that is selling the same boat with same motor. Motor is set to same height as mine now is. He uses a Michigan prop (not sure of material, painted black) 3 blade 10 3/4" x 12P. He says he gets 32 mph at 5400 rpm. Planes down to 15 mph.

Anyone have any thoughts or suggestions? Much appreciated.

Oh, and what do think of aluminum vs ss props? Heard aluminum can slip more. And 4 blade vs 3 blade?

 

[Jockey]

I have the same motor on a different hull I am very interested in hearing your results if you change props. Your speeds sound about what I get on my 17ft hourston.

What I have heard is with a 60hp motor you won't notice much difference by upgrading to a SS prop. The reason SS is better than aluminum is because the aluminum will flex under load but with only a 60hp motor there isn't enough power to make a noticable difference. The bigger the motor the more benefit you'll get out of your SS prop.

Changing the pitch or number of blades however may show results. If you try something let us know how it works out.

 

[Dave S]

I have the same motor on a different hull I am very interested in hearing your results if you change props. Your speeds sound about what I get on my 17ft hourston.

Changing the pitch or number of blades however may show results. If you try something let us know how it works out.

Thanks for that info on ss vs alum jockey. What prop do you have on your motor right now? Not sure if asking this is like asking a girl what she weighs, but what does she weigh? Your hourston that is.

 

[kayladog]

Before spending money on another prop you may want to try a whale tail (fins) on your leg. These provide more lift for easier planing and speed. I gained 2-3 mph.

 

[trendsetter]

Hey Dave,

What is the max horsepower rating for your Arima? It sounds like you are underpowered based upon the numbers you gave for your prop test.

Also, your prop slip is up around 28% which is bad. Ideal prop slip at full throttle is around 10%. Prop slip is calculated using RPM, gear ratio, prop pitch and speed.

In your case you may want to try a solas amita 4 blade aluminum 12" pitch prop. This should help reduce your prop slip and allow another 100-200 RPM compared to your current prop.

Don't bother with SS props; it's not going to make a big enough difference on your setup to justify the cost.

Iboats.com has very good deals on these solas props. I've bought 3 from them over the past couple years and shipping/cost is better than local.

Here's a link to the prop I was talking about: http://boatpropellers.iboats.com/Ya...0-Pitch_Amita_3313-108-12_Propeller/591/8573/

Cheers